The present invention relates generally to processor-controlled machines such as computers and more specifically to user interfaces for allowing a user to interact with the machine.
A frequent use of a processor-controlled machine such as a computer is to communicate information to a user of the machine and accept information from the user, thereby allowing the user to perform a specified task. Depending on the task at hand, the user will often make use of a task-specific application program such as a word processor (sometimes referred to as a text editor), a spreadsheet, a database, or a drawing program (sometimes referred to as a graphics editor). A reference to a specific type of program or editor is not intended to imply a stand-alone application program having only the particular functionality, since many programs have more than one type of functionality.
A typical application program consists of a set of instructions (the "application") that are executed in response to input signals to create and modify associated data (sometimes referred to as the underlying data). In many instances, this associated data is stored on a disk as a data file (sometimes referred to as "the file"), and portions are read into memory during program execution. For at least some applications, the data represents a document that is to be viewed (e.g., printed or displayed on a screen), and the application allows a user to modify the document.
In many instances, a user provides at least some of the input signals through one or more input devices, often a keyboard and a pointing device such as a mouse. By way of background, a mouse is a device that is moved over a work surface, typically next to the keyboard, and provides position signals so as to cause a cursor on the screen to move in accordance with the mouse's movements. The cursor is a special symbol that is used by an interactive program as a pointer or attention-focusing device. The mouse contains one or more pushbutton switches ("buttons") to provide additional input signals, which may be interpreted as part of a cursor event.
A display device, typically a visual display device such as a cathode ray tube (CRT) or a liquid crystal display (LCD), provides the user with information about the application and the underlying data, and allows the user to generate appropriate input signals and thus control the operation of the machine to produce the intended work product. The combination of input devices, display devices, and the nature of the information that the application provides the user may be thought of as the user interface to the application.
Although it is in principle possible for every application program to be entirely self-sufficient, it is almost universally the case that the application program executes in conjunction with an operating system ("OS"). The OS is a program that schedules and controls the machine resources to provide an interface between the application programs and the machine hardware. The OS typically provides the basic housekeeping functions that all application programs are likely to require, such as maintaining a file system, scheduling the CPU, receiving input from input devices, communicating with storage devices, sending data to display devices, and providing a generic mechanism according to which a user can manage files and cause various applications to execute. In the world of personal computers ("PCs") and workstations, operating systems are often associated with a particular type of hardware configuration, but this is not necessarily the case. Unix is an example of an OS that has been ported to run on many types of machine.
One type of operating system that has come into increasing use in recent years provides a graphical user interface ("GUI"). Apple Computer's Macintosh OS, IBM's OS/2, and Microsoft's Windows (actually a GUI shell that runs on top of a character-based operating system known as DOS) are the best known GUIs in the PC realm. The Macintosh OS has to date been available only on Apple's own Macintosh PCs based on the Motorola 680.times.0 family of microprocessors while OS/2 and Windows have only been available on so-called IBM-compatible PCs based on the Intel 80.times.86 family of microprocessors. This trend is in the process of changing, with Microsoft's Windows NT having versions capable of running on more than one type of microprocessor.
One relevant aspect of a GUI is that an open file for a given application is typically given a window, which is a movable and resizable region on the screen. The OS can have its own windows showing directory structures, with files and applications possibly being represented by icons (small graphical objects representing actions or items). There may be other windows that do not correspond to open files. An advantage of a GUI is that it provides a rather consistent user environment across applications. Some GUIs allow multiple applications to be open at the same time.
Regardless of the type of OS, the application program, with varying amounts of help from the OS, typically provides the user with a visible representation (sometimes referred to as the "screen image" or the "display image") of the underlying data. The user acts on the visible representation, and the program translates these actions to operations on the underlying data. As used herein, the term "visible representation" will refer to the visual representation of the underlying data not only for application programs, but for all kinds of programs, including the OS and various types of utility programs.
For example, in a word-processor, the underlying data consists of text with associated information specifying how the document will look when it is printed out on a printer. The associated information relates to document layout such as paragraphs and columns, and to text attributes such as font, size, style, and color. Depending on the particular word-processor and the operating system, the screen image may be limited to the text content, or may show the document substantially as it will appear when printed (WYSIWYG--pronounced "wizzywig," an acronym for "what you see is what you get"). A program designed for a character-based OS such as DOS is likely to provide something approaching the former, one designed for a GUI is likely to provide something approaching the latter.
A similar range of possible screen images will be found in other types of application programs. For example, in a drawing program, the underlying data will contain a description of each graphical object that will appear on the document. The description includes what is needed to give the object its intended appearance, including shape, size, line color and thickness, fill color and pattern, relative position in the plane of the document, and stacking order (whether the object is in front of or behind other objects). The screen image may show only the outlines of the objects (wireframe view) or may be a full WYSIWYG view.
Regardless of the type of application, the user manipulates input devices with reference to the screen image in order to effect desired changes. This is typically done by placing a cursor at a particular position on the screen that corresponds to the displayed location of an object to be modified, and executing one or more user events such as keystrokes or mouse actions. Mouse actions include button depression, button release, mouse movement, clicks, and drags. A mouse click refers to the user depressing and releasing one of the buttons without moving the mouse, but the term is also used to refer to the act of depressing one of the buttons. A drag (or sometimes click-and-drag) refers to the user positioning the cursor with the mouse, depressing one of the buttons, moving the mouse to a new position with the button still down, and releasing the button at the new location. The effect of mouse button depressions, mouse button releases, clicks, and drags may be modified by holding down a keyboard key or a different mouse button (if present).
For example, placing a cursor at a particular location in a word processor image may operate to insert typed text at that location. Dragging the cursor over a portion of the displayed text may select the text (shown on the screen as highlighted) so that the user can apply an operation (such as deleting, moving, or changing the font) to the selected text by some other mechanism. Depending on the application and the desired operation, the mechanism may be selecting the operation from a menu or entering a command from the keyboard.
Similarly, in a drawing program, the cursor can be placed in a mode by clicking on a tool icon (e.g., rectangle tool, line tool, polygon tool) so that subsequent clicks and drags with the cursor result in the creation of graphical objects. Clicking on an existing object with a plain cursor may result in selecting the object so that an operation may be applied via some other mechanism. If a drag is initiated with the cursor on an object, the result of the drag may be to cause the object to move along with the cursor, or may be to cause the object to be resized, depending on the cursor location on the object.
For users to be more productive, they should be provided with tools that are relatively easy to learn, easy to use, and powerful. These goals are sometimes easy to achieve individually, but rarely in combination. Nevertheless, considerable efforts have been expended in attempts to design user interfaces that are more intuitive, efficient, and versatile. The example discussed below, taken from the realm of drawing programs, shows the direction in which some of these efforts have led, and the way that improving one aspect of a user interface can degrade another.
A common configuration for drawing programs has a fixed tool palette to one side of the drawing area and a menu bar above the drawing area. To change tools, the user moves the cursor to the palette, clicks on the icon for the desired tool, and moves the cursor back to the appropriate location in the drawing area. To effect a desired operation on a desired object, the user moves the cursor to the object, clicks the object to select the object, moves the cursor to the menu bar, depresses the mouse button to pull down the menu, drags to the desired menu item, and releases the mouse button. The user then moves the cursor to the drawing area, to another item in the menu bar, or to the tool palette. This is a lot of mouse movement for even the simplest actions.
Tear-off menus and movable tool palettes allow the user to position what amount to permanently open menus and the tool palette near the area where drawing is actively occurring, and thereby reduce the length of mouse travel. Tear-off menus and movable palettes have made drawing more efficient in the sense of reducing the distances the user has to move the cursor, but have made it less efficient in another. They tend to take up a lot of the drawing area, especially near where the user is drawing. This can result in the user's constantly having to interrupt the drawing tasks to move the menus and palettes out of the way. This difficulty is compounded by the fact that as programs have gotten more powerful (greater functionality), the menus have grown longer and take up even more area. Unfortunately, this example of the trade-offs encountered in trying to meet the above goals is far from rare.